Research is being directed toward the determination of factors limiting diagnostic performance from dental radiographs. Of specific interest, is the consideration of task-specific questions from the point of view of information theory. Specific experiments involve selective manipulation of factors known to reduce the information capacity of radiographic displays. This is usually accomplished by introduction of unmodulated radiation to reduce the signal to noise power ratio. Although subject contrast is necessarily reduced in the process, system non-linearities may increase radiographic contrast under certain conditions. Related efforts include modeling complete radiographic systems in order to specify the influence of variations in spectral sensitivity of the detector, alternatives in beam geometry, changes in the energy distribution of the primary beam, scatter, etc. Predications based on these models suggest practical bases for optimizing specific radiographic tasks. BIBLIOGRAPHIC REFERENCES: Webber, R.L. and Folio, J.: Radiographic Detectability of Occipital and Temporal-Parietal Fractures Induced in Cadaver Heads. Journal of Trauma. 16: 115-124, 1976. Webber, R.L., Youmans, H.D., and Nagel, R.N.: A Nonlinear Model for Predicting Radiographic Contrast. Journal of Oral Surgery, Oral Medicine, Oral Pathology. 43: 798-811, 1977.